The present application describes systems and techniques relating to semiconductor-based imaging devices, for example, reducing fixed pattern noise in single-chip active pixel sensors.
A traditional design for an image sensor on a semiconductor chip consists of an image sensor array, column circuitry that includes a gain stage, an analog-to-digital converter and digital control logic to generate control signals. Traditional image sensors can introduce fixed pattern noise, which is undesirable in high-quality imaging systems, such as camera systems designed to operate in low light levels. A typical approach to suppress such fixed pattern noise is to add calibration circuitry, which generally increases design complexity and power requirements.